Muscles of the Pectoral Girdle & Upper limbs

What do appendicular muscles move

control upper and lower limbs and pectoral and pelvic girdles

What is another name for origin and insertion? Which one of these other names is mobile?

• proximal attachments and distal attachments for appendicular muscles

• Distal attachment is on the bone most likely to move

What is “muscle of the pectoral girdle”

a skeletal muscle that attaches to and moves the bones of the shoulder area

What are the names of the 7 muscles that move the pectoral girdle

1. Pectoralis minor

2. Serratus anterior

3. Subclavius

4. Trapezius

5. Levator scapulae

6. Rhomboid minor

7. Rhomboid major

pectoralis minor

Origin: Ribs 3-5

Insertion: the coracoid process of the scapula

Action: Protracts and depresses the scapula. 

N. supply: Medial Pectoral N.

Serratus anterior

Origin: Ribs

Insertion: the medial border of the scapula

Action: Protracts the scapula. 

N. supply: Long Thoracic N.

also called boxer muscle

 function of the subclavius muscle

stabilizes the clavicle and protects the nerves and blood vessels that pass underneath it

Trapezius Origin

The back of the skull

The spinous processes of T1-T12 vertebrae

Trapezius Insertion

The clavicle, the acromion and the spine of the scapula

Trapezius Action

Upper fibers: Elevate the scapula

Middle fibers: retract the scapula

Lower fibers: depress the scapula

Trapezius nerve supply

The accessory n. (CN XI)

Muscles attached to the medial border of the scapula

From top to bottom:

1- Levator scapula 

2- Rhomboid minor 

3- Rhomboid major

Muscles attached to the medial border of the scapula: What is their common origin

vertebral column

Muscles attached to the medial border of the scapula: Where does each of them insert

Levator scapula: above the level of the spine

Rhomboid minor: at the level of the spine

Rhomboid major: below the level of the spine

Muscles attached to the medial border of the scapula: What is their action

Elevation and retraction of the scapula.

What are the 2 main prime movers of the glenohumeral joint and also attach arms to trunk

• Latissimus dorsi posteriorly

• Pectoralis major anteriorly

7 scapular muscles

• Deltoid

• Coracobrachialis

• Teres major

• Rotator cuff muscles (4): subscapularis, supraspinatus, infraspinatus, teres minor

Which 2 muscles cross both the glenohumeral and elbow joints?

Biceps brachii and triceps brachii

Latissimus Dorsi

Origin: 

The thoracic vertebrae, iliac crest and the thoracolumbar fascia

Insertion: the intertubercular sulcus of the humerus

Action: 

Extension, adduction and medial rotation of the arm.

AKA: Swimmer’s muscle

N. supply: The thoracodorsal n.

Pectoralis Major

Origin: 

Medial part of the clavicle

Costal cartilages of ribs 

Sternum

Insertion: the lateral lip of the intertubercular sulcus of the humerus

Action:

Flexion, adduction and medial rotation of the arm.

N. supply: Lateral pectoral and medial pectoral nerves.

Deltoid

Origin: 

Acromial end of the clavicle, the acromion process and the spine of the scapula

Insertion: 

the deltoid tuberosity of the humerus 

Action: 

Anterior fibers: Flexion and medial rotation of the arm

Middle fibers: abduction of the arm

Posterior fibers: Extension and lateral rotation of the arm.

N. supply: The axillary n.

Teres Major

Origin: 

Inferior angle of the scapula

Insertion: 

Lesser tubercle of the humerus

Action: 

Extension, adduction and medial rotation of the arm

N. supply: The lower subscapular n.

Rotator Cuff Muscles

Posterior Surface of Scapula

• Supraspinatus

• Infraspinatus  

• Teres Minor                 

Anterior Surface of Scapula

• Subscapularis                        

All insert into the capsule of the shoulder joint to stabilize the shoulder

Anterior compartment of the arm

• Biceps brachii

• Brachialis

• Coracobrachialis

They are all innervated by the nerve that passes through the anterior compartment of the arm: the musculocutaneous nerve.

Biceps Brachii

Origin

long head: supraglenoid tubercle

short head: coracoid process

Insertion

The bicipital tendon inserts into the radial tuberosity and the bicipital aponeurosis.

Action

Elbow flexion

Weak flexor of the arm

Nerve Supply The Musculocutaneous n

What is the muscle of the posterior compartment of the arm

The Triceps muscle

Triceps

Origin

long head: the infraglenoid tubercle of the scapula

Insertion

The olecranon process of the ulna

Action

Elbow extension

Long head can extend the arm

Nerve Supply The radial n.

 pronators and supinators of the forearm

Pronators: palm faces posteriorly/downward

• Pronator teres

• Pronator quadratus

Supinators: palm faces anteriorly/upward

• Supinator

• Biceps brachii

Anterior compartment of the forearm has how many layers

3

Superficial layer of muscles of anterior compartment of forarm

• Pronator teres

• Flexor carpi radialis

• Palmaris longus

• Flexor carpi ulnaris

intermediate layer of muscles of anterior compartment of forarm

Flexor digitorum superficialis

deep layer of muscles of anterior compartment of forearm

• Flexor pollicis longus

• Flexor digitorum profundus

• Pronator quadratus

origin of anterior compartment of the forearm

Originates from the medial epicondyle of the humerus; commonly known as Golfer’s elbow. 

Palmaris longus: do we all have it?

10% - 15% of the population are missing the palmaris longus t

Flexor carpi radialis

Origin

Medial epicondyle of the humerus

Insertion

The base of the 2nd and 3rd metacarpal bones

Action

Flexion and abduction of the wrist

N. supply

The median nerve

Flexor digitorum superficialis:

Origin

Medial epicondyle of the humerus

Insertion

Middle phalanges of digits 2 through 5

Action

Flexion of the elbow and wrist

Flexion of the MCP & PIP of digits 2 through 5

N. supply

The median nerve

Muscles of the posterior compartment of the forearm

Extensor carpi radialis longus

Extensor carpi radialis brevis

Extensor digitorum

Extensor carpi ulnaris

Extensor pollicis longus

Extensor pollicis brevis

Extensor indicis

Extensor digiti minimi

Abductor pollicis longus

Extensor digitorum

Origin

Lateral epicondyle of the humerus (Tennis elbow)

Insertion

Distal and middle phalanges of digits 2 through 5

Action

Extension of the elbow and wrist

Extension of the MCP, PIPs & DIPs of digits 2-5

N. supply

The radial nerve

Extensor carpi ulnaris

Origin

Lateral epicondyle of the humerus

Insertion

The base of the 5th metacarpal bones

Action

Extension and adduction of the wrist

N. supply

The radial nerve

Intrinsic muscles of the hand

small muscles that are housed entirely in the palm, that divides into 3 groups

3 groups of the intrinsic muscles of the hand

• Thenar group

• Hypothenar group

• Midpalmar group

thenar group

muscles affect the motion of the thumb and include the following:

• Flexor pollicis brevis

• Abductor pollicis brevis

• Opponens pollicis

Hypothenar group

muscles affect the motion of the little finger and include the following:

• Flexor digiti minimi brevis

• Abductor digiti minimi

• Opponens digiti minimi

Midpalmar group

muscles affect the motion of all fingers and the thumb and include the following:

1. Lumbricals (flex the MCPs 2-5)

2. Dorsal interossei (abduction of digits 2-5) DAB

3. Palmar interossei (adduction of digits 2-5) PAD

4.  Adductor pollicis (adducts the thumb)